We surveyed 3,539 workers on Amazon's Mechanical Turk to gauge their response
to five scenarios describing scientific experiments---including one scenario
based on Facebook's emotional contagion experiment. Respondents who reported
being already aware of Facebook's experiment responded very differently to the
scenario based on it than those who reported being unaware, so we focused on
2,102 respondents who reported being unaware. We asked these respondents whether
they would want someone they cared about to be included as a participant,
interpreting an answer of `no' as indicating concern for participants. A greater
fraction of respondents were concerned about the two of the four scenarios
inspired by university-approved experiments than expressed concern for Facebook's
experiment. We also asked whether the experiment should be allowed to proceed,
interpreting a `no' answer as disapproval of the experiment. A similar or
greater fraction of respondents disapproved of the two more controversial
scenarios based on university-approved studies as disapproved of the
Facebook-experiment scenario. We found a statistically significant reduction
(for $\alpha=0.05$) in disapproval and concern for participants in a group of
respondents shown a hypothetical variant of Facebook's experiment in which the
manipulation performed by researchers was to insert extra positive posts into
users' news feeds---instead of removing positive or negative posts based on
treatment group.